OMRON C200H PLC Troubleshooting and Programming Essentials

Remote I/O ERROR B0/B1 communication fault check for the line between the master and slave stations

Special I/O Error D0 Special I/O Unit Error Check Unit Number (AR00), Reset (AR01)

BATTERY ERROR F7 Backup battery voltage low Replace battery (C200H-BAT09)

Fatal error (ALARM constantly on, RUN off)

Reason and countermeasures for message FAL number

CPU ERROR: No watchdog timeout (default 130ms). Check if the program is in a dead loop, or use WDT (94) to extend it

Memory Error F1: Check for missing, checksum errors, or illegal instructions in the memory unit installation and execute program checks

NO END INST F0 program does not have END (01). Add END (01) at the end of the program

I/O BUS ERROR C0-C2: Check for bus faults between CPU and I/O unit. Connect the rack cable and tighten the unit

TOO MANY UNITS E1 Special I/O Unit Number Duplicate, or SYSMAC LINK/NET Link Operation Level Conflict Check Unit Number Setting (0-9 Unique), Check Operation Level

FALS ERROR 01-99/9F program has executed FALS (07) or watchdog timeout. Check according to the FAL number; 9F indicates a period exceeding 130ms

3. Error History (CPU11-E)

DM0969-DM0999 stores the last 10 error records (error code, time, date). Enable AR0715 (Error History Enable Bit), and AR0713 determines whether to overwrite it. It can be reset through AR0714.

4. Application of arithmetic flags in programs

Compare the results of instruction CMP (20) and output them to GR (25505), EQ (25506), and LE (25507).

These flags must be used immediately after CMP, as END (01) will clear them.

Example: Compare HR09 and IR010, output according to different result settings.

Cycle time and I/O response time: key to timing sensitive applications

The cycle time of C200H includes: supervised processing+program execution+I/O refresh+peripheral services+link unit services (if any). Typical values: The supervision time of CPU01-E/03-E is 2.6ms, with a refresh time of 70 μ s for each input word and 40 μ s for each output word.

When the cycle time exceeds 100ms, SR25309 ON， And the 0.1 second clock pulse may not be accurate.

The maximum cycle time is stored in AR26, and the current cycle is in AR27.

Use SCAN (18) to set the minimum cycle time (CPU1-E).

The I/O response time (from input signal change to output action) depends on the input ON delay+cycle time x 1 or 2+output ON delay. If the input arrives before I/O refresh, the response is the fastest (one cycle); If it arrives after refreshing, it will take two cycles.